Apparatus for dividing or desurfacing metal by use of oxidizing sets



ma F s.s. WATTS Filed Aug'. 6, 1941 Oct.- 1, 1946.v

I APPARATUS FOR DIVIDING OR DESURFACING METAL BY-USE OF OXIDISING JETS Patented Oct. l, 1946 UNiTED STATE ArPARA'rUs `ron DIVIDING on DEsURFAc- E OF OXIDIZING'SETS I lSidney Sprague Watts, SouthgatejLondon N. 14,'

ING METAL BY Us Dany Y England, assigner to The British Oxygen Company Limited, London, England, a

British com- Y Application August 6, 1941, Serial No. 405,670 t j In Great The 'present invention relates to apparatus for dividing or desurfacing metal by use of an oxidizingjet and more particularly to apparatus for the supply of a stream of oxidizing gas for metal cutting and desurfacing operations.`

For cutting or desurfacing--metals, it is usual practice to preheaty themetal to its ignition temperature and then to-direct against the preheated surface a stream of oxidizing gas, vusually oxygen of substantial purity, Ihey apparatus commonly employed iorthispurpose comprises'a blowpipe having one passage to deliver'the stream of oxidizing gas, and another passage-or rseries of passages`v to deliver the gases for the preheating jet. The passage may beformed in asingle member or in a plurality of members arranged in a common-head. lIno'rder toV achieve a reasonably high cutting speed With such apparatus, especially when thick plate isto be cut, it is necessary to use an oxidizing vstream of high velocity. Difculty has, however, been experienced in obtaining clean cut surfaces especially when using a high velocity oxidizing* stream and,y in consequence, the speed of cutting hashad to be reduced.

The passage through which the stream of oxidizing gas is delivered has hitherto been of circular-cross section and investigation has shown that in its course through such a passage, a swirling motion is imparted to the gas stream. This swirling motion is believed to be the cause of faulty cuts and low cutting speed. It is an object ofk this "invention to provide means whereby such swirl is preventedand the oxidizing gas constrained to follow a substantially rectilinearpath.

According to one feature of the present invention, apparatus for dividing or desurfacing metal by the use of an oxidizing jet comprises a passage for the delivery of a stream of oxidizing gas to a surface to be cut or desurfaced, the passage being of non-'circular cross section in order to prevent or substantially to reduce any tendency for the gas to assumev a swirling motion in its course.

through the passage.

In cross section the oxidizing gas passage may be elliptical, triangular, square orany other convenient non-circular shape. When the velocity of the gas stream is low as in the case of deseaming, a passage may be used which is elliptical in cross-section, in other words, one which shows no substantial departure from circularity as this may sumce to reduce any incipient swirl to negligible proportions, but with increasing velocities it is necessary to provide more abrupt changes iu the circumferential direction, namely, by using Britain September 20, 1940 l 5 Claims. (Cl. 158-274) 2 e e a passage which is triangular, square or of other cross sectional shape which is distinctly non-circular, if the swirling of thegas is to be inhibited' to the desired extent. Alternatively, the tendency for the gas toassume a swirling motion may be prevented bythe provision of balile means which offer no substantial obstru'ction to the iiow of gas in the longi-i tudinal direction'but'whichprevent the. gasirom' swirling around` thewallsrof thepassa'ge.. flhe" baille means may be formed integrally withthe walls of the passage or may be constituted by a unit which is mountedin .the passage and'either secured-to' the wall'thereof or'merelycontacting therewith atapluralit'yof points. 1 It is preferred that the baille means be located as near as possible to the delivery end of the 'passage, for example, terminating close to the outlet of the nozzle of a gas cutting torch, but it'may be disposed some distance from the delivery end if the passage be'of smooth bore so that no turbulence is impartedto the gas after emerging 'from the baille means, f Y i' The invention will now be more particularly described with reference to the accompanying drawing in which: Fig. 1 'is aview'in perspective of Ya` nozzle embodying the features of the inventionfas shown in central vertical section. l Fig. 2 is a horizontal cross-sectional view taken midway of the length of the nozzle memberY and shows a desirable modification in structuraliorm. Fig. 3 is a similar view of a further modification. I Fig. 4 is a similar horizontal sectional view: of astill further modification, and. l J Figs. 5 to 10 are isometric views showing alternative forms of baffle means, the other parts of the nozzle being omitted except for the wall of the oxidizing gas passage which is shown in dotted lines.

The same reference numerals out for equivalent parts.

The nozzle comprises an internal member 20 having an axial passage 2l for conveying a stream of oxidizing gas and an external member 22 disposed concentrically with respect to the internal member 20, a passage 23 being formed between the two members for the delivery of a stream of preheating gas, such as a mixture of oxygen and acetylene. |An internally threaded union 24 is provided for securing the member 22 to an external thread on the body of the torch (not shown) and the internal member 20 is screwthreaded at the end remote from the tip in order are used throughthat it may be secured to a complementary screwthread formed internally in the head of the torch. The oxidizing gas passage at the inlet end is wider than at the outlet where it is constricted to form a jet. The baille means comprise a ilat plate 25:l which. extends throughout the length of the wider portion of the passage 2| and diametrically across it making a sliding iit with the wall. The constricted portion is of circular cross-seotion and of smooth bore so as to prevent any4 swirl being set up after the gas leaves the wider part of the passage Where the baille is located'. Such baille means may readily bei inserted; in existing types of blowpipe torches. As is the casewith the baille means shown in the other gures, swirling of the gas around thewa-ll of the-passage is prevented or at least substantially reducedV by the plate 25 and a gas stream having enhanced cutting properties is thereby obtained.

As shown in Fig. 2, theA passage 2l is altered to be triangular in'` cross-section,r whilst according td Fig'..3, thepassage 2|I is. square and has inaddition baille means the form of diagonally extending iins 25 which meet at? the centre to form four passages. each. triangular inv cross-section. The passage 2l shown in Fig. 4 is roughly starshaped in` cross-section. With all these forms of passage, any tendency to swirling is largely inhibited and the gasV issues from the nozzle with high longitudinal velocity suitable for the production of' clean cuts.v

As shown in Fig., 5,. the baille means consists of a sheet of metal 25 bent into the form of a triangle: which makes a sliding llt within the wall of the passage 2.1. In Fig. 6 the baille means consists of metal strips 25l arranged in cruciforrn fashion.-

With the constructions shown in Figs. '7 and 8, swirling of the cutting gas is prevented by subdividing the` gas streams into a plurality of separate. channels formed, as shown in Fig. 7, by a bundle of tubes 25, or as shown in Fig; 8, by a cylinder 25 provided with longitudinally extending apertures.

In the modification shown in Fig. 9 the baille l means consists of a hollow elongated, box-like structure 25 with concave surfaces open at each end. As shown in Fig. 10i. the baille means consists of an elongated structureV which is stai'- shaped in cross-section.

What is claimed is:

1. A nozzle. for a blowpipe. torch comprising a member a cylindrical axial passage for an oxidizing gas, a relatively short delivery passage of relatively lesser diameter thanA said cyf' lindrical axial passage for'forming said gas into 4 a jet, a tapering transition passage between said axial passage and said delivery passage, and antiswirl means in said axial passage and extending to said tapering transition passage for delivering'thereto a gas stream having reduced swirl characteristic.

2. A nozzle for a blowpipe torch comprising a member having a cylindrical axial passage for an oxidizing gas, a relatively short delivery passage of relatively lesser diameter than said cylindrical axial passage for forming said gas into a jet, a tapering transitionv passage between said axial passage and saidv delivery passage, and means for dividing said cylindrical axial passage lengthwise into a plurality of' anti-swirl channels extending to. said tapering transition passage for delivering theretoa. gas stream having reduced swirl characteristic. V

3. A- nozzle for a blowpipe torch comprising a member having a cylindrical axial passage for an oxidizing gas, a relatively short delivery passage of relatively lesser diameter than said cylindrical axial passage for forming said gas into av jet,v a tapering transition passage between said axial passage and said delivery passagel andA a cruciform anti-swirl baille device. extending lengthwise of said cylindrical axial passage to said ta.- pering transition passage for. delivering thereto a gas stream having reduced swirl characteristic. s 4. A nozzle fora blowpipe-torch comprising a member having a cylindrical axial passage for an oxidizing gas, a relatively short delivery passage of relatively lesser diameter than said cylindrical axial passage for forming said gas into a jet, a tapering transition passage between said axial passage and said delivery passage, and a cylindrical baille. device fitted in said cylindrical axial passage and provided with a plurality of open ended anti-swirl channels extending lengthwise thereof to said tapering transitionpassage for delivering thereto a gas stream having reduced swirl characteristic. l

5. AV nozzle for Ia blowpipe torch comprising a member having a cylindrical axial passage for an oxidizinggas, a relatively shortv deli-Very passage of relatively lesser diameter than said cylindrical axial passage for forming said gasintoa jet, a tapering transition passage between said` axial passage and said delivery passage, and a hollow open ended anti-swirl baille device located in said cylindrical axial passager and pro-vided with concave walls, said baille device extending to said tapering transition. passage for delivering thereto al gas stream having `reduced swirl characteristic.

SIDNEY SPRAGUE WATTS. 

